Trading Securities (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	$ 101,097,000	$ 91,616,000	$ 190,591,000
Trading Securities, Net Unrealized Gain (Loss)	57,000	11,000	(2,502,000)
Trading Securities, Pledged as Collateral	0	0	0
U.S. Government agency debentures [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	19,027,000	34,120,000	60,713,000
Trading Securities, Net Unrealized Gain (Loss)	6,000	77,000	(552,000)
U.S. agency residential mortgage-backed securities [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	13,540,000	21,011,000	43,858,000
Trading Securities, Net Unrealized Gain (Loss)	3,000	123,000	38,000
Municipal and other tax-exempt securities [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	32,950,000	27,350,000	53,819,000
Trading Securities, Net Unrealized Gain (Loss)	28,000	(182,000)	(1,271,000)
Other trading securities [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	35,580,000	9,135,000	32,201,000
Trading Securities, Net Unrealized Gain (Loss)	$ 20,000	$ (7,000)	$ (717,000)